Arrangement in air blast circuit breaker provided with damping resistance



Jan. 5, 1954 ORWALD 2,665,351

HF ARRANGEMENT IN AIR BLAST CIRCUIT BREAKER PROVIDED WITH DAMPING RESISTANCE Filed Feb. 6, 1952 INVENTOR //MA 0A//5/?W4w ATTORNEY UNITED STATES PATENT OFFICE ARRANGEMENT IN AIR BLAST CIRCUIT BREAKER PROVIDED WITH DAMPIN G RESISTANCE Haakon Forwald, Ludvika, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a Swedish corporation Application February 6, 1952, Serial No. 270,170

Claims priority, application Sweden February 9, 1951 Claims. (Cl. 200148) In air blast circuit breakers for high tension circuit breaker. The operatin g members will be it is often necessar to couple the breaklng gap hereinafter described in con nection with a dein parallel with a resistance in order to damp scription of the function of the circuit breaker. overtensions which may occur. In order to When opening the circuit breaker a press avoid a too great heating of this resistance, the 5 button 23 is pressed, so that a circuit is closed circuit breaker generally is so designed that the from the operating battery 24 through the coil resistance is disconnected a short time after the 25 on the release magnet 26. When the armaarc has been extinguished. Circuit breakers of ture of this magnet is released the spring 21 this kind have thus been provided with a sepwill move the piston 29 in the cylinder 28 uparate member for connecting and disconnecting wards, and the rod 30 attached to this piston the resistance. will act on the stem 3| in the operating valve The present invention, however, has for its 32. When the stem 3! moves upwards, the valve object to provide a device for such circuit breakdisc 33 will close the outlet from the operating ers in which the said connecting and disconvalve 32 and open a communication from the necting of the resistance is performed by means operating pipeline 34 of the on. of the same member that controls the flow of the pipeline 35 leading from a source of comcompressed air to the breaking gap. pressed air. When compressed air is supplied On the accompanying drawing one form of through the pipeline 34 it will et on th lower a circuit breaker according to the invention is surface of the piston 36 in the time lag memb shown. On the drawing I designates a com- 31. The piston then moves cuit breaker to pressed air container which is provided with a pressing the spring 38 and raising th stem at Wall 2 on which the movable contact of the ciruntil the latter acts on the ste 4| of the valve cuit breaker together with the contact for the 42. The lower end of the stem 46 1s at the connecting in of the resistance is mounted. The point 39 pivotally connected to the piston 35 stationary contact of the circuit breaker is des- 25 When the valve disc 43 in th ignated by 3 and is attached to the conductor upwards, it closes the outl t 4 in an insulating bushing 5 projecting into the pressed air pipelin 44 t 013 compressed air container. The movable contact tion from the cylinder I7, thro of the circuit breaker is designated by 6 and is 45, to the open air.

in the form of a. tube 1 attached to a piston is When the disc 43 moves upwards so that air 8 which is movable in a cylinder 9 attached to f om the cylinder I! can flow out thro h he the wall 2. I 0 is a sliding contact surroundpipeline 45, compressed air from the container mg the tubular contact I for the transmission I will flow through the channels 53 in the pisof the current from the contact 6 to the cylton l6 and act on the left side of the piston inder 9. H designates the damping resistance 3-3 and move it against the action of the spring [8 which suitably consists of a cylinder of sintered so that the valve disc I9 leaves the seat or silicon carbide. This cylinder is carried by an t ghtening ge 0, and the tubular contact I5 insulator I2 fastened in the wall of the concomes into contact with the yieldable contact tainer I, and the resistance 1 l is connected at M of the resistance ll. Compressed air is preone end over a conductor l3 with the stationary 4o Vented from flowing to the right side of'the contact 3 of the circuit breaker. The other end p ton I 6 by the back valve 54 which consists of the resistance H is provided with a contact of a Spring actuated ring forced against the M, which contact is suitably mounted in yieldholes 55, and said back valve 54 serves to maining relation to the resistance. The connection tain the container, to the r ght of said wall 2, of the resistance H in parallel to the contact 45 fill d With air under pressure. Simultaneously pair 3 6 is effected by means ,f a tubular with the upward movement of the piston 35, a

operating pipeline I5 is provided With a valve disc I 9 which when device 37 is opened, and co its packing is forced against the annular formed e C mpressed air pipeline 3 ridge 20 blocks the escape of compressed air pipeline 4! to diaphragm t t valve from the container I. The container 5 with. all When compressed air horn the pipeline 4! acts the parts attached to it is carried by an insun the diaphragm 49 and thus on the Valve disc lating pillar 2| which is suitably attached to a the Valve d sc 5! in the valve 48 is moved casing 22 containing operating members for the 5 upwards and closes the left compressed air pipeline 44 at the same time as a communication is opened through the pipeline 52 from the cylinder 9 to the open air. When the cylinder 9 is thus emptied, the air in the container I will act on the pisto 8 and move it to the left against the action of the spring 8 the contact 6 then moving away from contact 3. The compressed air will then escape from the container I through the contact fijand will serve to extinguish the 'arc and will'subsequently escap through the tube 1 and through the outlet valve I9, 20.

The time lag device 31 has for its-object to close, after a predetermined time, the outlet yalvel is,

20 and to open the breaking gap iii, 15 and this is effected by the means whereby the aiiflowing into the cylinder 48 with a speed regulated by ,the restriction screw 51 acts on the piston 58 whichlby means of the pin 52 moves the stem llrtolthe side against the action ,of the spring fili. 'The valve stem M is then liberated so that the spring :81 can movethe valve disc :43 downwards so that the communication with the open air from the cylinder I! is closed and compressed air from the right hand outlet of the compressed air pipeline M can flow through the pipeline 45 to the cylin- .jder l1 and can there act on the right hand side ofxthe piston l and thus counter-act the pressure on its left hand side, so that the spring is can move the piston it to the left thus closing the outlet valve |'9, 20 and opening the contactpair i l, 15.

During the motion to the left of the contact 15 compressed air from'thecontaine'r escapes through the contact [5 and through the openingss62 close to the valve disc'i9 and frcin'there through the outlet valve 19, 2E and thus extinguishes the are caused by the current through the resistance Ii.

In order to'make possible an extinction of the are between the contacts H5 and 1:5, bet-ore the valve 19, 29 has been closed, the motion of the piston i6 is delayed to a certain extent by choosing a suitable cross section of the channels 53 near the center of the piston 16.

When closing thebircuit breaker the press button 23 is pressed and then a circuit is formed from the operating battery 24 through the solenoidi63. The valve stem' in the valve s i is then moved upwards so that the outlet opening from the valve is closed by the valve disc 85, while the valve disc 66 leaves its seat, so that compressed air' from the pipeline 35' can fiow through the pipeline 5? to the cylinder 28 and there act on the piston 29, to move it downwards until theblrmature in the release magnet; 23 is again attracted. When the piston 28'moves downwards, the stem 3| is moved downwards by the action of the spring 31 so that'thecommunication between thecompres'sed airpipeline 35 and the pipeline $4 is closed and the pipeline 34'is brought into communication with the open air.' The spring 38 will then move the piston 36 downwards, so that the stem 46 will return to its original position in alignment with the stem 41 after the evacuation of the time lag-device 31. The closing of the main breaking gap is now effected by evacuating the pipeline ii after the piston 38 is on its way towards its lower position so that the disc 59 moves downwards, and the disc 5: closes the outlet opening from the valve 8. When the valve disc 5! moves downwards, the left hand outlet from the compressed air pipeline 64 is opened, so that compressed air can flow through the pipeline 52 to the cylinder 9 and can there act on the 'mon for the two two main breaking gaps piston 8, so that the contact 6 is moved against the contact 3 by the action of the spring 8'.

In spite of the fact that the circuit breaker on the drawing is provided withonlyonemain breakinggap and one damping resistance with breaking contacts, it can of course also be provided with and two damping resistances coupled in parallel with them but with one air bla st or outlet valve for the two main breaking gaps, common for the two main breaking gaps-and further the outlet pipe l5 may be combreaking gaps disconnecting the damping resistances in that the tube I5 is provided with :a fork shaped part forming a contact bridge making contact with the two contacts I4.

I claim as my invention:

.1.v An :air' blast circuit breaker comprising a .;,compressed air container, an insulating support for said container, a

wall dividing said container into two compartments, openings in said wall, a main breaking contact pair mountedin one of said com-pa'rtments'in close proximity to one of 's'aid openings, a damping resistance coupled in parallel with said contact pair, an aukiliarycontact pair connected in series with said darnping resistance and located in close proximity: to 'another of said openings, pneumatic means for operating said main and auxiliary breaking contacts, an outlet valve from the otherfcom partmerit, means connecting said valve with the movable contact of said auxiliary contact pair, a time lag device for the pneumatic operating means of said. movable auxiliary contact, and means whereby' said time lag device effects an .immediate closing but a delayed reopening of said auxiliary contact pair.

2. A circuit breaker according to claim 1, comprising an air operated piston for said time lag device, a stem pivoted "to said piston, an operating valve for the auxiliary contact pair, a stem extending from said operatingvalve in alignment with the said pivoted stem, a delayed air operated device for moving said pivoted stem out 'of alignment with said valve stem, and a spring for returning said pivoted stem to the aligned position.

3. An air blast circuit breaker comprising a compressed air container, an insulating support for said'cont'a iner, a wall dividing'the container into two compartments, an opening in saidwall', a fixed main contact in one of'sa'id compartments, a main'tubular movable contact extend-i ingthrough said opening and providing communication between said compartments, a' second opening in said wall, a'fiiied auxiliary contact, a movable tubular auxiliary contact mounted in said second opening" and providing communication' between said compartments, a damping resistance connected in -parallel with the main contact pair andin series'with the auxiliary'contact pair, a valve carried by said auxiliary movable contact for controlling the escape of tompressed air from said compartments, and a time lag device for the operation of saidmovablefaukiliary contact, said device including means for efiecting an immediate closing but a dlayed'reopening of said auxiliary contact pair.

4. 'A circuit breaker according to claim 3, comprising cylinders carried by said wall, pistons mounted in said cylinders and carrying said tubular main and auxiliary movable contacts, and spring and pneumatic means for actuatingsa'id pistons in their cylinders to open and close the contact pairs alternately.

5; A circuit breaker according to claim}, comprising a cylinder carried. by said wall, a piston in said. cylinder actuated by spring and pneumatic means and carrying said tubular auxiliary Contact, restricted channels for the passage of compressed air through said piston from one of said compartments to one end of the cylinder to move said piston and to close said auxiliary contact pair, and a back valve for controlling the fiow of air between said cylinder and one of said compartments.

HAAKON FORWALD.

Number Number UNITED STATES PATENTS Name Date Trencham Apr. 4, 1939 FOREIGN PATENTS Country Date Great Britain Aug. 27, 1947 Great Britain Nov. 3, 1948 

